Charles Mingus, that great pioneer of instrumental music, once remarked that he couldn't play a particular solo without thinking about hate and persecution. The song in question, "Haitian Fight Song" (a tribute to the island's slave revolt of 1801), is filled with fire and determination. Listening to the song, it's impossible not to feel that something important is being conveyed, or as Mingus himself put it, "It usually ends with my feeling [that] 'I told them! I hope somebody heard me.'"

Mingus' idea of putting concrete ideas into strictly instrumental music is the challenge that faces the members of the Coma Lilies and Seeded Skies, two local instrumental bands. It's not that they hate words. Ask them what's been on their nightstand lately and they'll rattle off Vonnegut and Hesse. Or take them to a library, where I met up with them on a recent Sunday afternoon, and you'll find the high-volume instrumental band members rather chatty among the quiet, hallowed walls of books.

In an age where lyrics are more prominent than ever in popular music and singers are instantly groomed to be celebrity symbols, starting an instrumental band seems like an alienating act. However, the popularity of such groups as Tortoise, Trans Am and Mogwai have blown open a door for instrumental indie rock, however under-the-radar it may be.

The Coma Lilies' eponymous album, recorded earlier this year, is the sound of expansive ambition channeled through frets and keys. A strong moment comes in the form of "Have Fun at Your War," a riff-cluttered epic with varying levels of texture. The provocative title, the band says, is meant to convey a certain idea. "We put a lot of mind into our music," says bassist Brian Kincaid, 19. "We're here to write music that we feel will express what we're trying to express."

"It takes some part on the listener to have an open mind," adds 19-year-old guitarist Hunter Ellis, "so it's a two-way situation." Over the past two years, the Coma Lilies have found enough such listeners to headline shows and make a name for themselves--no small feat for a band with no singer.

"I don't think we're intentionally alienating ourselves from the mass culture," continues Ellis, "but I'd say we are definitely taking a step back and separating ourselves." Most fans who come to see the band aren't concerned with image, anyway, says keyboardist Asher Katz. "Young people are more open to instrumental music," says the 17-year-old.

Have the Coma Liles ever toyed with the idea of getting a singer? "We had a fat drunk guy in San Marcos ask us if he could sing for us," laughs Ellis. "We got the show over the Internet. Don't trust the Internet."

Seeded Skies have a less structured, more improvisational approach to their instrumental songs. On Clockwise, the band's new CD, Andrew Maurer has established himself as a dizzying guitarist to be reckoned with. The 18-year-old says he never listens to the radio, but he is no stranger to the library's CD collection.

"I've flipped through all these about 30 times," he says, and pulling out a compilation of Hawaiian choral chants, adds, "This one here is pretty great."

Such varied influences have only added to Maurer's playing style, though he usually lets bassist Michael Bellonio and drummer Ross Harris create the framework for Seeded Skies' compositions. Without a vocalist, the members are allowed space to strive for musical ideas. In the instrumental medium, Maurer points out, "The guitar lines are singable, you can hum them."

Ellis jumps in on this idea of composition. "I'll hear it in my head," he says, "I'll hum what I hear, and then play what I hum."

"So in a lot of ways," summarizes Maurer, ignoring the supposed detriment of having no lead vocalist, "you're singing through the instrument."

The Coma Lilies perform with Toast Machine, Life in Braille and Archeopteryx on Friday, Oct. 1, at Clo's Parkside Grill, 557 Summerfield Road, Santa Rosa. 7:30pm. $8. 707.539.6100. Seeded Skies are on hiatus until December while Ross Harris is globetrotting in Argentina, that lucky bum.